If you absolutely want to stop seeing these features, there are 2 possibilities:
1) Change your display options: Tools/Options/View-Select/Display of tangent edges of parts/Assemblies. Select "Removed". Let's see if it doesn't become disturbing for you in other situations
2) If it's only for representation, select all the entities of your guide curve (right click "Select chain"), then Tools/Spline Tools/Fit Spline. Your original strokes go into construction and a spline is superimposed.